Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications
Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorp...
Published in: | Chemical Geology |
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Main Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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Elsevier
2017
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Subjects: | |
Online Access: | http://eprints.esc.cam.ac.uk/3855/ http://eprints.esc.cam.ac.uk/3855/1/1-s2.0-S0009254117300463-main.pdf https://doi.org/10.1016/j.chemgeo.2017.01.022 |
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ftucambridgeesc:oai:eprints.esc.cam.ac.uk:3855 |
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openpolar |
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Open Polar |
collection |
University of Cambridge, Department of Earth Sciences: ESC Publications |
op_collection_id |
ftucambridgeesc |
language |
English |
topic |
01 - Climate Change and Earth-Ocean Atmosphere Systems 02 - Geodynamics Geophysics and Tectonics |
spellingShingle |
01 - Climate Change and Earth-Ocean Atmosphere Systems 02 - Geodynamics Geophysics and Tectonics Struve, Torben van de Flierdt, Tina Burke, Andrea Robinson, Laura F. Hammond, Samantha J. Crocket, Kirsty C. Bradtmiller, Louisa I. Auro, Maureen E. Mohamed, Kais J. White, Nicholas J. Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
topic_facet |
01 - Climate Change and Earth-Ocean Atmosphere Systems 02 - Geodynamics Geophysics and Tectonics |
description |
Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorporated into their skeletons. We here present new results on modern specimens of Desmophyllum dianthus, Balanophyllia malouinensis, and Flabellum curvatum, collected from the Drake Passage, and Madrepora oculata, collected from the North Atlantic. All modern individuals were either collected alive or uranium-series dated to be < 500 years old for comparison with local surface sediments and seawater profiles. Modern coral Nd isotopic compositions generally agree with ambient seawater values, which in turn are consistent with previously published seawater analyses, supporting small vertical and lateral Nd isotope gradients in modern Drake Passage waters. Two Balanophyllia malouinensis specimens collected live however deviate by up to 0.6 epsilon units from ambient seawater. We therefore recommend that this species should be treated with caution for the reconstruction of past seawater Nd isotopic compositions. Seventy fossil Drake Passage CWCs were furthermore analysed for their Nd concentrations, revealing a large range from 7.3 to 964.5 ng/g. Samples of the species D. dianthus and Caryophyllia spp. show minor covariation of Nd with 232Th content, utilised to monitor contaminant phases in cleaned coral aragonite. Strong covariations between Nd and Th concentrations are however observed in the species B. malouinensis and G. antarctica. In order to better constrain the source and nature of Nd in the cleaned aragonitic skeletons, a subset of sixteen corals was investigated for its rare earth element (REE) content, as well as major and trace element geochemistry. Our new data provide supporting evidence that the applied cleaning protocol efficiently removes contaminant lithogenic and ferromanganese oxyhydroxide phases. Mass balance calculations and seawater-like REE patterns rule out lithogenic and ferromanganese oxyhydroxide phases as a major contributor to elevated Nd concentrations in coral aragonite. Based on mass balance considerations, geochemical evidence, and previously published independent work by solid-state nuclear magnetic resonance (NMR) spectroscopy, we suggest authigenic phosphate phases as a significant carrier of skeletal Nd. Such a carrier phase could explain sporadic appearance of high Nd concentrations in corals and would be coupled with seawater-derived Nd isotopic compositions, lending further confidence to the application of Nd isotopes as a water mass proxy in CWCs. |
format |
Article in Journal/Newspaper |
author |
Struve, Torben van de Flierdt, Tina Burke, Andrea Robinson, Laura F. Hammond, Samantha J. Crocket, Kirsty C. Bradtmiller, Louisa I. Auro, Maureen E. Mohamed, Kais J. White, Nicholas J. |
author_facet |
Struve, Torben van de Flierdt, Tina Burke, Andrea Robinson, Laura F. Hammond, Samantha J. Crocket, Kirsty C. Bradtmiller, Louisa I. Auro, Maureen E. Mohamed, Kais J. White, Nicholas J. |
author_sort |
Struve, Torben |
title |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_short |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_full |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_fullStr |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_full_unstemmed |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_sort |
neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - modern calibration and evaluation of palaeo-applications |
publisher |
Elsevier |
publishDate |
2017 |
url |
http://eprints.esc.cam.ac.uk/3855/ http://eprints.esc.cam.ac.uk/3855/1/1-s2.0-S0009254117300463-main.pdf https://doi.org/10.1016/j.chemgeo.2017.01.022 |
geographic |
Drake Passage |
geographic_facet |
Drake Passage |
genre |
Antarc* Antarctica Drake Passage North Atlantic |
genre_facet |
Antarc* Antarctica Drake Passage North Atlantic |
op_relation |
http://eprints.esc.cam.ac.uk/3855/1/1-s2.0-S0009254117300463-main.pdf Struve, Torben and van de Flierdt, Tina and Burke, Andrea and Robinson, Laura F. and Hammond, Samantha J. and Crocket, Kirsty C. and Bradtmiller, Louisa I. and Auro, Maureen E. and Mohamed, Kais J. and White, Nicholas J. (2017) Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications. Chemical Geology, 453. pp. 146-168. ISSN 0009-2541 DOI https://doi.org/10.1016/j.chemgeo.2017.01.022 <https://doi.org/10.1016/j.chemgeo.2017.01.022> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.chemgeo.2017.01.022 |
container_title |
Chemical Geology |
container_volume |
453 |
container_start_page |
146 |
op_container_end_page |
168 |
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1766262574584692736 |
spelling |
ftucambridgeesc:oai:eprints.esc.cam.ac.uk:3855 2023-05-15T13:55:44+02:00 Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications Struve, Torben van de Flierdt, Tina Burke, Andrea Robinson, Laura F. Hammond, Samantha J. Crocket, Kirsty C. Bradtmiller, Louisa I. Auro, Maureen E. Mohamed, Kais J. White, Nicholas J. 2017 text http://eprints.esc.cam.ac.uk/3855/ http://eprints.esc.cam.ac.uk/3855/1/1-s2.0-S0009254117300463-main.pdf https://doi.org/10.1016/j.chemgeo.2017.01.022 en eng Elsevier http://eprints.esc.cam.ac.uk/3855/1/1-s2.0-S0009254117300463-main.pdf Struve, Torben and van de Flierdt, Tina and Burke, Andrea and Robinson, Laura F. and Hammond, Samantha J. and Crocket, Kirsty C. and Bradtmiller, Louisa I. and Auro, Maureen E. and Mohamed, Kais J. and White, Nicholas J. (2017) Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications. Chemical Geology, 453. pp. 146-168. ISSN 0009-2541 DOI https://doi.org/10.1016/j.chemgeo.2017.01.022 <https://doi.org/10.1016/j.chemgeo.2017.01.022> cc_by CC-BY 01 - Climate Change and Earth-Ocean Atmosphere Systems 02 - Geodynamics Geophysics and Tectonics Article PeerReviewed 2017 ftucambridgeesc https://doi.org/10.1016/j.chemgeo.2017.01.022 2020-08-27T18:09:49Z Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorporated into their skeletons. We here present new results on modern specimens of Desmophyllum dianthus, Balanophyllia malouinensis, and Flabellum curvatum, collected from the Drake Passage, and Madrepora oculata, collected from the North Atlantic. All modern individuals were either collected alive or uranium-series dated to be < 500 years old for comparison with local surface sediments and seawater profiles. Modern coral Nd isotopic compositions generally agree with ambient seawater values, which in turn are consistent with previously published seawater analyses, supporting small vertical and lateral Nd isotope gradients in modern Drake Passage waters. Two Balanophyllia malouinensis specimens collected live however deviate by up to 0.6 epsilon units from ambient seawater. We therefore recommend that this species should be treated with caution for the reconstruction of past seawater Nd isotopic compositions. Seventy fossil Drake Passage CWCs were furthermore analysed for their Nd concentrations, revealing a large range from 7.3 to 964.5 ng/g. Samples of the species D. dianthus and Caryophyllia spp. show minor covariation of Nd with 232Th content, utilised to monitor contaminant phases in cleaned coral aragonite. Strong covariations between Nd and Th concentrations are however observed in the species B. malouinensis and G. antarctica. In order to better constrain the source and nature of Nd in the cleaned aragonitic skeletons, a subset of sixteen corals was investigated for its rare earth element (REE) content, as well as major and trace element geochemistry. Our new data provide supporting evidence that the applied cleaning protocol efficiently removes contaminant lithogenic and ferromanganese oxyhydroxide phases. Mass balance calculations and seawater-like REE patterns rule out lithogenic and ferromanganese oxyhydroxide phases as a major contributor to elevated Nd concentrations in coral aragonite. Based on mass balance considerations, geochemical evidence, and previously published independent work by solid-state nuclear magnetic resonance (NMR) spectroscopy, we suggest authigenic phosphate phases as a significant carrier of skeletal Nd. Such a carrier phase could explain sporadic appearance of high Nd concentrations in corals and would be coupled with seawater-derived Nd isotopic compositions, lending further confidence to the application of Nd isotopes as a water mass proxy in CWCs. Article in Journal/Newspaper Antarc* Antarctica Drake Passage North Atlantic University of Cambridge, Department of Earth Sciences: ESC Publications Drake Passage Chemical Geology 453 146 168 |